For our next, increasingly late, freetext, let's take a crack at a good ol' staple of the adventure genre: Acid. Just think where we'd be without the stuff. No Melf's Acid Arrows. No pools of acid in Metroid. No acid-sprayer guns. No acid rain, or acid-scarred faces. Truly, it would be a sadder, more basic world, if probably a safer one for fictional characters.

Gladiator! Or Gladiatrix(!) if you prefer. I want hardened warriors, dedicated to entertaining the masses through the spectacle of mortal combat. Or places where they do it. Or people who train them. Or plots centered around them. Or planets which are secretly places used to breed hardy warriors for the entertainment of great space-faring races. Anything, really.